Horton

Re: pg_dump versus ancient server versions

Peter Eisentraut <peter.eisentraut@enterprisedb.com>

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From: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Andrew Dunstan <andrew@dunslane.net>, Bruce Momjian <bruce@momjian.us>, Robert Haas <robertmhaas@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-12-03T16:29:41Z
Lists: pgsql-hackers 
On 02.12.21 23:16, Andres Freund wrote:
> I think we should at least include pg_upgrade in this as well, it's pretty
> closely tied to at least pg_dump.

right

>> * pg_dump and psql will maintain compatibility with servers at least
>>    ten major releases back.
> 
> Personally I think that's too long... It boils down keeping branches buildable
> for ~15 years after they've been released. That strikes me as pretty far into
> diminishing-returns, and steeply increasing costs, territory.

Well, it is a lot, but it's on the order of what we have historically 
provided.

> I realize it's more complicated for users, but a policy based on supporting a
> certain number of out-of-support branches calculated from the newest major
> version is more realistic. I'd personally go for something like newest-major -
> 7 (i.e. 2 extra releases), but I realize that others think it's worthwhile to
> support a few more.  I think there's a considerable advantage of having one
> cutoff date across all branches.

I'm not sure it will be clear what this would actually mean.  Assume 
PG11 supports back to 9.4 (14-7) now, but when PG15 comes out, we drop 
9.4 support. But the PG11 code hasn't changed, and PG9.4 hasn't changed, 
so it will most likely still work.  Then we have messaging that is out 
of sync with reality.  I can see the advantage of this approach, but the 
communication around it might have to be refined.

> I think we should explicitly limit the number of platforms we care about for
> this purpose. I don't think we should even try to keep 8.2 compile on AIX or
> whatnot.

It's meant to be developer-facing, so only for platforms that developers 
use.  I think that can police itself, if we define it that way.

Commits

  1. Remove psql support for server versions preceding 9.2.

  2. Clean up some more freshly-dead code in pg_dump and pg_upgrade.

  3. Remove pg_dump's --no-synchronized-snapshots switch.

  4. Remove pg_upgrade support for upgrading from pre-9.2 servers.

  5. Remove pg_dump/pg_dumpall support for dumping from pre-9.2 servers.

  6. Suppress -Warray-bounds warning in 9.2's xlog.c.

  7. Suppress -Wformat-overflow warnings in 9.2's xml.c.

  8. Disable -Wsometimes-uninitialized warnings in the 9.2 branch.

  9. Fix function return type confusion

  10. Fix compiler warning

  11. Silence another gcc 11 warning.

  12. Suppress uninitialized-variable warning in guc.c.

  13. Suppress -Warray-parameter warnings in pgcrypto/sha2.c.

  14. Reformat imath.c macro to remove -Wmisleading-indentation warnings.

  15. Clean up compilation warnings coming from PL/Perl with clang-12~

  16. Make ecpg's rjulmdy() and rmdyjul() agree with their declarations.

  17. Use -Wno-format-truncation and -Wno-stringop-truncation, if available.

  18. Make pg_upgrade's test.sh less chatty.

  19. Add checks for valid multibyte character length in UtfToLocal, LocalToUtf.

  20. Use return instead of exit() in configure

  21. Add support for Visual Studio 2019 in build scripts